Technology

Measured carefully, so surgery is planned for your eye.

What each test is for, what it feels like and how long it takes.

Lenstar LS900 and ZEISS IOLMaster 700 optical biometers

Measures the length of your eye and the curve of your cornea with light, to set the power of your new lens.

What it is like: A few seconds per eye, looking at a small light. Nothing touches the eye.
How long: A few minutes

In a very dense cataract light cannot pass through, so ultrasound is used as well.

Heidelberg Spectralis OCT

Layer-by-layer images that show problems in the retina and track glaucoma damage to the nerve.

What it is like: You look at a target while it scans. Drops may widen your pupils first, blurring near vision for a few hours.
How long: Usually under ten minutes

A scan supports a diagnosis; it never makes one on its own.

Automated perimetry

Maps your side vision, where glaucoma damage shows first, often before you notice.

What it is like: You look at a central light and press a button each time a flash appears.
How long: About 15 to 30 minutes for both eyes

It takes concentration. Tell the staff if you need a break.

Operating microscope and phacoemulsification system

A magnified view for the surgeon, and an ultrasound probe that breaks up and removes the clouded lens.

What it is like: You lie still with the eye numbed. You may see light and movement, not the instruments.
How long: Usually well under an hour

Often called "laser surgery" by mistake. Standard phaco uses ultrasound, not a laser.

Nd:YAG laser

Clears a hazy capsule after cataract surgery, and treats narrow-angle glaucoma.

What it is like: You sit at the laser and may hear clicks. There is no cut into the eye.
How long: A few minutes

Your pupil may be widened first, so bring someone to drive you home.

Before your tests

Some tests use drops that widen your pupils, blurring your vision for a few hours.

Bring someone with you if you can, and do not plan to drive home.
Bring your glasses and, if you wear them, your contact lenses and their case.
Bring a list of your medicines, including eye drops and blood thinners.
Allow time. A first visit with tests can take a few hours.